Trim their claw will help. And take some time to play with you cat, burn some of his energy.
I had the same problem before, so I get a hamster for the small cat, redirect her attention to other things, and let the old cat adjust.
How's you cats doing? Does your kitty still very active?
My hamster is in a cage, or inside a running ball, so the cats never have a chance to touch it. They enjoy watching the hamster running around and sometimes talk to it. http://www.youtube.com/watch?v=4J-XtmWnNOM
now my 2 cats get along very well, they can sit / sleep / eat next to each other. The older cat is the kung fu master now, and chase back the young cat.
